1.4.5
Surds
Surds
Surds
Surds are expressions like 3√6. They contain irrational numbers. These are numbers which can't be expressed as normal numbers or as a fraction. The rules for surds are:










Simplifying Surds
Simplifying Surds
If the number inside the root has a factor which is a square number the surd can be simplified.
Rationalising the Denominator
Rationalising the Denominator
It is often easier to work with surds when there are no square roots on the bottom of a fraction. Removing surds from the bottom of a fraction is called ‘rationalising the denominator’.


Advanced example
Advanced example
- To rationalise a denominator of the form a ± √b multiply by the denominator but with the sign in front of the root changed.


Exact form
Exact form
- Leaving an answer in exact form means leaving any fractions, surds and constants like in the expression rather than giving the answer as a decimal.
1Numbers
1.1Integers
1.3Decimals
1.4Powers & Roots
1.5Set Language & Notation
1.6Percentages
1.7Ratio & Proportion
2Equations, Formulae & Identities
2.1Algebraic Manipulation
2.2Expressions & Formulae
2.3Linear Equations
2.4Quadratic Equations
2.5Proportion
3Sequences, Functions & Graphs
3.1Sequences
3.3Graphs
3.4Common Graphs
4Geometry
4.1Angles, Lines & Triangles
4.2Polygons
4.5Circle Properties
4.6Trigonometry & Pythagoras’ theorem
4.7Mensuration of 2D Shapes
4.83D Shapes & Volume
5Vectors & Transformation Geometry
6Statistics & Probability
6.1Statistical Measures
6.2Graphical Representation of Data
Jump to other topics
1Numbers
1.1Integers
1.3Decimals
1.4Powers & Roots
1.5Set Language & Notation
1.6Percentages
1.7Ratio & Proportion
2Equations, Formulae & Identities
2.1Algebraic Manipulation
2.2Expressions & Formulae
2.3Linear Equations
2.4Quadratic Equations
2.5Proportion
3Sequences, Functions & Graphs
3.1Sequences
3.3Graphs
3.4Common Graphs
4Geometry
4.1Angles, Lines & Triangles
4.2Polygons
4.5Circle Properties
4.6Trigonometry & Pythagoras’ theorem
4.7Mensuration of 2D Shapes
4.83D Shapes & Volume
5Vectors & Transformation Geometry
6Statistics & Probability
6.1Statistical Measures
6.2Graphical Representation of Data
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